CN107844213B - touch sensing unit - Google Patents

Abstract

A touch sensing unit is disclosed. The touch sensing unit includes a touch sensor, a sensor line, a piezoelectric region, and a touch sensor controller. The touch sensors are arranged in an island shape. The sensor lines are connected to the touch sensors. The piezoelectric regions overlap the touch sensor and are arranged in an island shape. The touch sensor controller receives a voltage from the piezoelectric region when the piezoelectric region receives the pressure and determines a magnitude of the pressure based on the voltage.

Description

touch sensing unit

Korean Patent Application No. 10-2016-0120130, filed on Sep. 20, 2016, entitled "Display Device", is hereby incorporated by reference in its entirety.

technical field

One or more embodiments described herein relate to a touch sensing unit.

Background technique

Laptops, mobile phones, portable multimedia players, tablet personal computers, and other electronic devices have displays, some of which are accompanied by touch screens for detecting the position of a user's finger or stylus.

SUMMARY OF THE INVENTION

According to one or more embodiments, a touch sensing unit includes: a substrate; a touch sensor on the substrate and arranged in an island shape; a sensor line connected to the touch sensor; a piezoelectric region overlapping the touch sensor and in an island shape and a touch sensor controller that receives a voltage from the piezoelectric region when the piezoelectric region receives pressure, and determines a magnitude of the pressure based on the voltage. The piezoelectric area can directly contact the touch sensor.

The touch sensing unit may include an insulating layer coating the touch sensor and the piezoelectric region. The touch sensing unit may include a common electrode on the insulating layer, wherein the common electrode overlaps the piezoelectric region. The piezoelectric region may include polyvinylidene fluoride (PVDF) polymer, carbon nanotube (CNT)/PVDF, ZnO nanowires, lead-free Mn-doped (K _0.5 , Na _0.5 )NbO ₃ , PZT, Pb(Zr, At least one of Ti)O ₃ and Pb(Zr _1-x Ti _x )O ₃ . The piezoelectric region may have a light transmittance of about 80% or more.

As the distance from the terminal portion increases, the size of the piezoelectric region can be increased. The touch sensing unit may include: an elastic layer between the touch sensor and the piezoelectric region; and an insulating layer coating the piezoelectric region. The touch sensing unit may include a common electrode on the insulating layer, wherein the common electrode overlaps the piezoelectric region. The touch sensor can receive the AC component of the voltage generated from the piezoelectric region, rather than the DC component. The touch sensor and the sensor line may be integrally formed.

According to one or more other embodiments, a touch sensing unit includes: a substrate; a touch sensor on the substrate and including a transmission electrode and a reception electrode; a sensor wire connected to the reception electrode; a piezoelectric region overlapping the reception electrode and are arranged in an island shape; and a touch sensor controller receives a voltage generated by the piezoelectric region through a receiving electrode when pressure is applied to the piezoelectric region, and determines the magnitude of the pressure. The piezoelectric region may be in direct contact with the receiving electrode.

The touch sensing unit may include a common electrode overlapping the piezoelectric region, wherein the common electrode is insulated from the piezoelectric region. The piezoelectric region may include polyvinylidene fluoride (PVDF) polymer, carbon nanotube (CNT)/PVDF, ZnO nanowires, lead-free Mn-doped (K _0.5 , Na _0.5 )NbO ₃ , PZT, Pb(Zr, At least one of Ti)O ₃ and Pb(Zr _1-x Ti _x )O ₃ . As the distance from the terminal portion increases, the size of the piezoelectric region can be increased.

The touch sensing unit may include: an elastic layer between the receiving electrode and the piezoelectric region; and an insulating layer coating the piezoelectric region. The elastic layer may include a first elastic layer and a second elastic layer, and the elastic modulus of the first elastic layer and the elastic modulus of the second elastic layer may be different from each other.

The touch sensing unit may include a common electrode on the insulating layer, wherein the common electrode overlaps the piezoelectric region. The receiving electrodes may receive the AC component of the voltage produced by the piezoelectric region, rather than the DC component.

Description of drawings

Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, in which:

Figure 1 shows one type of display device;

Figure 2 shows one type of touch sensor controller;

Figure 3 shows an embodiment of a touch sensing unit;

Figure 4 shows a view along section line II' in Figure 3;

5A and 5B illustrate an example of the operation of the touch sensing unit;

Figure 6 shows another embodiment of a touch sensing unit;

7A and 7B illustrate other examples of the operation of the touch sensing unit;

FIG. 8 shows an embodiment of generating a voltage by a pressure sensor;

9A-9C illustrate an example of the operation of the pressure sensor;

Figure 10 shows an embodiment of a touch sensor controller;

Figure 11 illustrates an embodiment of the operation of a touch sensor;

FIG. 12A shows another embodiment of a touch sensor pattern, and FIG. 12B shows another embodiment of the operation of the touch sensor pattern;

Figure 13 shows another embodiment of a touch sensor pattern; and

Figure 14 shows another embodiment of a touch sensor pattern.

Detailed ways

Example embodiments have been described with reference to the accompanying drawings; however, example embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will convey exemplary embodiments to those skilled in the art. Embodiments (or portions thereof) may be combined to form further embodiments.

In the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. In addition, it will be understood that when a layer is referred to as being "under" another layer, it can be directly under the other layer, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present . The same reference numbers refer to the same elements throughout.

When an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or be indirectly connected with one or more intervening elements interposed therebetween or incorporated into the other element. Additionally, when an element is referred to as "comprising" a component, unless a different disclosure exists, this means that the element can also include the additional component, rather than exclude the additional component.

FIG. 1 shows a type of display device including a display panel 300, a scan driver 400, a data driver 500, a touch sensor, a touch sensor controller 700 coupled to the display panel 300, and a scan driver for controlling the display panel 300. 400 and the signal controller 600 of the data driver 500 .

The display panel 300 includes a plurality of scan signal lines G1 to Gn, a plurality of data lines D1 to Dm, and a plurality of pixels Px connected to the scan signal lines G1 to Gn and the data lines D1 to Dm. The display panel 300 may include a touch sensing unit embedded therein, the touch sensing unit including the touch sensors Ts connected to the sensor lines SL1 to SLp and arranged in a matrix form. The touch sensor Ts and the sensor lines SL1 to SLp may be integrally formed. A separate touch sensing unit including the touch sensor Ts may be attached to the front surface portion of the display panel 300 .

The scan signal lines G1 to Gn extend substantially in the row direction and transmit gate signals including gate conduction for turning on switching elements such as thin film transistors (“TFTs”) connected to each pixel Px voltage and gate-off voltage capable of turning off the switching element.

The data lines D1 to Dm extend substantially in the column direction, and transmit data voltages when the switching elements connected to each pixel Px are turned on.

Each pixel Px is spatially arranged to emit light of one of a plurality of primary colors. In one case, multiple pixels Px may display primary colors over time. Therefore, a desired color can be represented by combining the primary colors in space and time. A common voltage and a data voltage can be applied to each pixel Px.

The signal controller 600 receives input image signals R, G, and B and one or more control signals CONT (eg, a horizontal synchronization signal, a vertical synchronization signal, a clock signal, a data enable signal, etc.) from an external graphics processing unit. The signal controller 600 processes the image signals R, G, and B based on the image signals R, G, and B and the control signal CONT according to operating conditions of the display panel 300, and generates and outputs the image data DAT, the gate control signal CONT1, the data control signal CONT2 and clock signal. The signal controller 600 also outputs the synchronization signal Sync to the touch sensor controller 700 .

The gate control signal CONT1 includes a scan start pulse vertical signal STV for instructing the start of scanning and a clock pulse vertical signal CPV for generating a gate-on voltage. The output period of the scanning start pulse vertical signal STV corresponds to one frame (or refresh rate). The gate control signal CONT1 may also include an output enable signal OE that defines the duration of the gate-on voltage.

The data control signal CONT2 includes a horizontal start signal and a load signal. The horizontal start signal indicates the start of the transfer of the image data DAT for the pixels in one line. The load signal instructs the transmission of the corresponding data voltages to the data lines D1 to Dm.

The scan driver 400 applies a gate-on voltage and a gate-off voltage to the scan signal lines G1 to Gn according to the gate control signal CONT1.

The data driver 500 receives the data control signal CONT2 and the image data DAT from the signal controller 600, converts the image data DAT into data voltages based on the gray-scale voltages from the gray-scale voltage generator, and applies the data voltages to the data lines D1 to Dm. The data voltages may include data voltages of positive polarity and data voltages of negative polarity. Data voltages of positive and negative polarities may be alternately applied on a frame, row, and/or column basis.

The sensor lines SL1 to SLp extend substantially in the row direction or the column direction, and are connected to the respective touch sensors Ts to transmit touch detection signals and sensor signals. The touch sensor Ts may generate sensor signals based on touch in a self-capacitance manner. The touch sensor Ts may receive touch detection signals from the sensor lines SL1 to SLp, and output a sensor signal reflecting a capacitance change due to a touch of an external object (eg, a finger or a stylus) to the touch sensor through the sensor lines SL1 to SLp Controller 700.

In addition, the touch sensor Ts may generate a sensor signal based on a touch in a mutual capacitance method. The mutual capacitance type touch sensor Ts includes a touch transmission electrode Tx and a touch reception electrode Rx. The touch transmission electrodes Tx are sensor electrodes for transmitting touch detection signals, and the touch reception electrodes Rx are electrodes for receiving touch detection signals to generate sensor signals.

FIG. 2 shows the application of the touch sensor controller 700 to the touch sensor Ts of the self-capacitance type. The touch sensor controller 700 generates and transmits a touch detection signal to be applied to the touch sensor Ts, and receives the sensor signal from the touch sensor Ts to generate touch information.

The touch sensor controller 700 includes a timing generation unit 710 , a signal generation and/or processing unit 720 , a signal transceiver 730 and a multiplexer 740 . The timing generation unit 710 generates and outputs the scan enable signal TSE based on the synchronization signal Sync from the signal controller 600 . The signal generation and/or processing unit 720 generates and outputs the touch detection signal TSS based on the scan enable signal TSE. The signal transceiver 730 converts the touch detection signal TSS into an analog signal. The multiplexer 740 selectively applies the touch detection signal TSS to the sensor lines SL1 to SLp.

The capacitance change caused by the touch may be output as a sensing signal from the touch sensor Ts through the sensor lines SL1 to SLp. The sensor signals are transmitted to the signal generation and/or processing unit 720 through the multiplexer 740 and the signal transceiver 730 . The signal generation and/or processing unit 720 decodes the sensor signal and compares the sensor signal with the touch detection signal TSS to generate touch information (eg, presence of touch input or touch location). For example, when a finger touches the touch sensor Ts, the amplitude of the sensor signal may be smaller than that of the touch detection signal TSS. The signal generation and/or processing unit 720 may calculate the voltage difference to determine whether a touch has occurred.

FIG. 3 illustrates an embodiment of a touch sensing unit, and FIG. 4 is a cross-sectional view taken along line II′ of FIG. 3 . 3 and 4 , the touch sensing unit includes a substrate 810 , a touch sensor Ts, a pressure sensor Ps, an insulating layer 840 and a protective layer 850 . The substrate 810 may be a transparent glass substrate, a plastic substrate, or a front substrate of a display device.

The touch sensor Ts may use one touch sensor Ts in a self-capacitance manner to detect touch. The touch sensors Ts are located on the substrate 810, are arranged in the first and second directions (eg, the X direction and the Y direction), and are connected to the sensor lines SL1 to SLp, respectively. The touch sensor controller 700 is connected to the touch sensor Ts through the sensor lines SL1 to SLp. The sensor signal output from the touch sensor Ts may be applied to the touch sensor controller 700 through a terminal portion under the substrate, for example.

The pressure sensor Ps is located on the touch sensor Ts. The lower portion of the pressure sensor Ps may directly contact the upper portion of the touch sensor Ts, and may have an area smaller than that of the touch sensor Ts. The pressure sensor Ps may include, for example, a piezoelectric element. The piezoelectric element includes a first electrode 831 , a piezoelectric layer 832 and a second electrode 833 . One piezoelectric element may not be connected to another piezoelectric element, may be arranged in an island shape, for example, and may be independent of each other.

The first electrode 831 contacts the upper surface of the touch sensor Ts, and electrically connects the piezoelectric layer 832 and the touch sensor Ts. The first electrode 831 may include a transparent conductive material, eg, indium tin oxide (ITO), indium zinc oxide (IZO), or carbon nanotubes (CNT).

The piezoelectric layer 832 on the first electrode 831 includes a stack of piezoelectric materials that generate electricity through pressure. The piezoelectric element is a voltage generating element using a piezoelectric phenomenon, for example, when the piezoelectric layer 832 contracts or expands due to external pressure, polarization is caused by a change in the internal stress of the piezoelectric layer 832 and a voltage is generated. Piezoelectric layer 832 may be, for example, a polymer including polyvinylidene fluoride (PVDF), carbon nanotube (CNT)/PVDF, ZnO nanowires, lead-free Mn doped (K _0.5 , Na _0.5 )NbO ₃ , PZT, Pb (Zr,Ti)O ₃ or PbZr _1-x Ti _x O ₃ films. In one embodiment, the piezoelectric layer 832 may include a plurality of layers stacked in the thickness direction. The piezoelectric layer 832 may have a thickness of, for example, about 80 μm or less, and may have light transmittance. In one embodiment, the thickness of piezoelectric layer 832 may be about 10 μm or less.

The second electrode 833 is located on the piezoelectric layer 832 and may include, for example, a transparent conductive material.

The insulating layer 840 is on the piezoelectric element, can be used to attach the substrate 810 to the protective layer 850, and can coat the upper and side surfaces of the piezoelectric element. In one embodiment, the insulating layer 840 may include polydimethylsiloxane (PDMS) having excellent elasticity.

The protective layer 850 protects the touch sensor Ts and the pressure sensor Ps, and provides a touch surface to the user. The protective layer 850 may include a flexible film to allow externally applied pressure to be effectively transmitted to the pressure sensor Ps. In one embodiment, the protective layer 850 may include a glass coating film or a hard coating film. When the substrate 810 is the front substrate of the display device, the protective layer 850 may include, for example, a polarizing film.

In FIG. 3 , the lengths of the sensor lines SL1 to SLp differ depending on, for example, the positions of the touch sensors Ts on the substrate. As the length of the sensor lines SL1 to SLp increases, the sensor signal is attenuated by the voltage drop. The area of the touch sensor Ts may increase proportionally as the distance between the terminal portion and the touch sensor Ts increases. The voltage drop based on the length deviation of the sensor lines SL1 to SLp can be offset by adjusting the area of the touch sensor Ts, so that the touch sensor controller 700 can detect the touch position based on the sensor position without correcting the voltage drop.

In addition, as the distance between the terminal portion and the touch sensor Ts increases, the size of the pressure sensor Ps on the touch sensor Ts can also increase proportionally. The pressure can be detected without correction based on the position of the pressure sensor Ps. This can be achieved, for example, by adjusting the area ratio of the pressure sensor Ps. The amount of data processed by the touch sensor controller 700 can be reduced by area correction, so that the touch position and pressure can be detected more quickly.

5A and 5B illustrate an example of the operation of the touch sensing unit.

5A , when a touch object (eg, a finger) approaches or touches the front surface of the touch sensing unit, a touch capacitor is formed on a path indicated by a dotted line between the touch sensor Ts and the touch object. The touch sensor controller 700 applies a touch detection signal including a plurality of pulse waves to the touch sensor Ts, and detects a sensor signal of the touch sensor based on the applied touch detection signal. When a touch does not occur, a predetermined sensor signal voltage is detected based on the applied touch detection signal according to an RC delay determined based on the structures of the touch sensing unit and the touch sensor Ts.

In an exemplary embodiment, when an external touch occurs as shown in FIG. 5A , a touch capacitor is formed between the touch object and the touch sensor Ts. The touch capacitor increases the RC delay and detects a smaller voltage as the sensor signal of the touch sensor Ts with respect to substantially the same touch detection signal. The touch sensor controller 700 can detect changes in sensor signals and determine a touch that occurs at the touch sensor Ts.

Referring to FIG. 5B , the touching object may deform the substrate downward by applying pressure to the insulating layer. A potential difference is generated between the opposing electrodes of the pressure sensor Ps by an externally applied pressure. The generated voltage of the pressure sensor Ps is transmitted as a sensor signal to the touch sensor controller 700 through the sensor lines SL1 to SLp connected to the touch sensor Ts. The generated voltage of the pressure sensor Ps may have a larger value than the sensor signal detected in the touch operation. The touch sensor controller 700 may analyze the voltage of the sensor signal to determine the location and magnitude of the applied pressure.

FIG. 6 shows an embodiment of a mutual capacitance type touch sensing unit. Referring to FIG. 6 , the touch sensor Ts of the touch sensing unit includes a touch transmission electrode Tx and a touch reception electrode Rx. The touch transfer electrodes Tx extend in one direction of the panel and face the touch receiving electrodes Rx arranged parallel to the extending direction of the touch transfer electrodes Tx. Eight touch reception electrodes Rx are shown in FIG. 6 to correspond to one touch transmission electrode Tx. The number of touch transmission electrodes Tx and touch reception electrodes Rx may be different in other embodiments, eg, based on the touch resolution of the touch sensing unit.

The touch receiving electrodes Rx may be connected to the touch sensor controller 700 through the sensor lines SL1 to SLp. The touch sensor controller 700 may determine the touch sensor Ts corresponding to the touch based on the touch detection signal applied to the touch transmission electrode Tx, and may analyze the sensor signal detected from the touch reception electrode Rx.

7A and 7B illustrate an example of the operation of the touch sensing unit.

7A , the mutual capacitor type touch sensing unit includes a substrate 810 , a touch transmission electrode Tx, a touch reception electrode Rx, a pressure sensor Ps, an insulating layer 840 and a protective layer 850 . The touch transmission electrodes Tx and the touch reception electrodes Rx are located on substantially the same surface on the substrate 810 and face each other on a plane. The touch transmission electrodes Tx and the touch reception electrodes Rx may be formed on substantially the same layer including substantially the same material. Examples of electrode materials may include transparent conductive oxides (TCO) such as indium tin oxide (ITO) and indium zinc oxide (IZO), conductive nanowires such as silver nanowires (AgNW), and metal meshes.

The pressure sensor Ps is located on the touch receiving electrode Rx, and may include a piezoelectric element. The piezoelectric element includes a first electrode 831 , a piezoelectric layer 832 and a second electrode 833 . One piezoelectric element is not connected to the other piezoelectric element, and is arranged in an island shape independently of each other.

In order to electrically connect the piezoelectric layer 832 and the touch sensor Ts, the first electrode 831 of the piezoelectric element contacts the upper surface of the touch sensor Ts. The first electrode 831 may include a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or carbon nanotube (CNT).

The piezoelectric element generates a voltage difference between the first electrode 831 and the second electrode 833 based on the external pressure. Piezoelectric elements can be made, for example, by stacking polymers such as polyvinylidene fluoride (PVDF), carbon nanotubes (CNT)/PVDF, ZnO nanowires, lead-free Mn-doped (K _0.5 , Na _0.5 )NbO ₃ , PZT, Pb (Zr,Ti)O ₃ and PbZr _1-x Ti _x O ₃ piezoelectric materials. Piezoelectric elements can be formed directly on electrodes by laminating piezoelectric materials. When formed in a deposition method, the piezoelectric element may be directly deposited on the touch receiving electrode Rx without using the first electrode 831 .

The insulating layer 840 is on the piezoelectric element and may attach the substrate 810 to the protective layer 850 . The insulating layer 840 may include, for example, an adhesive having excellent light transmittance or polydimethylsiloxane (PDMS) having excellent elasticity.

The protective layer 850 protects the touch sensor Ts and the pressure sensor Ps, and provides a touch surface to the user. The protective layer 850 may include a flexible film to allow externally applied pressure to be effectively transmitted to the pressure sensor Ps. In one embodiment, the protective layer 850 may include a film such as a glass-coated film or a hard-coated film. When the substrate 810 is the front substrate of the display device, the protective layer 850 may include, for example, a polarizing film.

In order to detect a touch action, the touch transmission electrode Tx transmits a pulse wave as a touch detection signal to be transmitted through a capacitor. When no touch action is made, the charging voltage may be based on the touch detection signal transmitted from the touch transmission electrode Tx to the touch reception electrode Rx. The charging voltage can be set as a reference voltage.

When a user touches the protective layer 850 as shown in FIG. 7A , a touch capacitor is formed between the touch transfer electrode Tx and the touch object. A portion of the touch detection signal output from the touch transfer electrode Tx may leak through the touch capacitor. Therefore, the position detection signal is not entirely transmitted to the touch receiving electrode Rx according to the amount of leakage. Therefore, the touch detection signal transmitted to the touch reception electrode Rx may have a smaller voltage than the charging voltage in the untouched state.

The touch sensor controller 700 may detect the position of the touch based on the comparison of the sensor signal applied to the touch receiving electrode Rx and the reference voltage. When a pressure is applied after a touch is input as in FIG. 7B , a potential difference is generated between the opposing electrodes of the pressure sensor Ps above the touch receiving electrode Rx. FIG. 7B shows that a positive voltage is generated in the pressure sensor Ps in the direction in which the electrodes are in contact with the touch receiving electrodes Rx.

FIG. 8 illustrates an example of generating a voltage by a pressure sensor according to an exemplary embodiment, and more particularly, illustrates the voltage generated by the pressure sensor Ps according to the size of the touch applied to the touch sensor Ts and the pressure sensor Ps located above the touch sensor Ts. An example of the magnitude of the pressure sensor voltage Vf produced in .

Referring to FIG. 8 , part A shows an example of a state in which a touch occurs only on the surface of the touch sensing unit. The touch sensor Ts can detect the position in the part A where a touch occurs. In such an exemplary embodiment, no additional pressure is applied to the pressure sensor Ps. Therefore, the pressure sensor voltage Vf can be detected as about 0V.

Part B shows an example of a state in which the user presses the surface of the touch sensing unit with a relatively weak force. The front surface of the touch sensing unit includes a flexible substrate or protective film. A portion of the front surface of the touch sensing unit is recessed inward due to a weak pressing force of the user. Therefore, a relatively weak pressure is applied to the pressure sensor Ps. The pressure sensor Ps generates a relatively low pressure sensor voltage Vf corresponding to a weak external pressure.

Section C shows an example of a state in which the user presses the surface of the touch sensing unit with a relatively strong force. The front surface of the touch sensing unit is deformed by the user's strong pressing force, and applies a strong pressure to the pressure sensor Ps. The pressure sensor Ps generates a relatively high pressure sensor voltage Vf corresponding to a strong external pressure.

FIG. 8 schematically shows the magnitude of the pressure sensor voltage Vf generated by the pressure. The pressure sensor voltage Vf actually measured from the outside can be changed according to the configuration of the connection circuit. In one embodiment, the pressure sensor Ps has a structure in which at least one electrode is not connected to another wiring. Therefore, the touch sensor controller can detect the AC component of the pressure sensor voltage Vf through the touch receiving electrode Rx. For example, a touch sensor controller can detect voltage changes caused by pressing. Therefore, offset noise caused by peripheral electronic devices can be blocked by removing the DC component of the pressure sensor voltage Vf.

9A , 9B and 9C illustrate the operation of a pressure sensor according to an exemplary embodiment based on an equivalent circuit diagram of a mutual capacitance type touch sensing unit.

FIG. 9A shows an example of an operation circuit diagram of the touch sensing unit in the case where the user does not touch. Referring to FIG. 9A, AC power used as a touch detection signal is output from the touch sensor controller. Mutual capacitors Cm (eg, parasitic capacitors) may be formed between the touch transmission electrodes Tx and the touch reception electrodes Rx facing and opposing each other. The touch sensor controller connected to the touch receiving electrode Rx detects the sensor signal voltage V _RX of the touch receiving electrode Rx.

The touch detection signal may be applied to the touch transmission electrode Tx to be transmitted to the touch reception electrode Rx through the mutual capacitor Cm. The sensor signal voltage VRX of the touch receiving electrode _Rx is determined based on the RC delay of the resistance component and the capacitance of the mutual capacitor Cm determined according to the structure and material of the touch sensing unit.

FIG. 9B shows an example of an operation circuit diagram of the touch sensing unit in a state where a touch is made. Referring to FIG. 9B , the touch capacitor Ct is formed between the touch transfer electrode Tx and the touch object, and is separated from the mutual capacitor Cm. A part of the touch detection signal of the touch transfer electrode Tx may flow through the touch capacitor Ct. As a part of the touch detection signal is transmitted to the touch capacitor Ct, the sensor signal voltage VRX applied to the touch receiving electrode _Rx may be detected to be smaller than the sensor signal voltage _VRX of FIG. 9A . The touch sensor controller can detect the touch state of each touch sensor by detecting the sensor signal voltage V _RX .

9C shows an example of an operating circuit diagram of a touch sensing unit in which pressure is applied to the touch sensing unit to generate a voltage from the pressure sensor. Referring to FIG. 9C , the touch capacitor Ct formed between the touch transfer electrode Tx and the touch object continues to be maintained. For example, as the distance between the touch transfer electrode Tx and the touch object is narrowed, the size of the touch capacitor Ct can be increased.

A potential difference is generated between the opposing end electrodes of the pressure sensor Ps to which pressure is applied externally, and a pressure sensor voltage Vf is output. One electrode of the pressure sensor Ps is directly connected to the touch receiving electrode Rx, and the pressure sensor voltage Vf is applied to one terminal of the mutual capacitor Cm. The pressure sensor voltage Vf may be greater than the sensor signal in an untouched state.

Because the piezoelectric element generates a DC voltage, the pressure sensor voltage Vf is represented as DC power in the circuit diagram. However, the pressure sensor Ps according to the exemplary embodiment has a structure in which one electrode is connected to the common electrode in series with the capacitor. An open circuit is formed on the DC power supply. A closed circuit is formed on the AC circuit. Therefore, only the AC component (eg, the voltage fluctuation component) of the pressure sensor voltage Vf can be transmitted to the touch receiving electrode Rx.

FIG. 10 shows an embodiment of a touch sensor controller 700 that measures the touch position of the touch sensor Ts and the pressure generation of the pressure sensor Ps. The touch sensor controller 700 generates a touch detection signal and transmits the touch detection signal to the touch sensor Ts. The touch sensor controller 700 receives sensor signals from the touch sensor Ts to generate touch information. In addition, the touch sensor controller 700 analyzes the voltage of the sensor signal to determine the sensor signal factor due to the pressure sensor Ps.

The touch sensor controller 700 may include a timing generation unit 710 , a signal generation and/or processing unit 720 , a signal transceiver 730 , a multiplexer 740 and a pressure signal analysis unit 750 . The timing generation unit 710 , the signal generation and/or processing unit 720 , the signal transceiver 730 and the multiplexer 740 may be substantially the same as those corresponding to the embodiments in FIGS. 1 and 2 .

The pressure signal analysis unit 750 analyzes the change of the sensor signal applied from the area determined to have been touched. Since the touch action occurs before the pressure is applied to the pressure sensor Ps of the touch sensing unit, the determined value of the touch sensor Ts may be referred to.

The pressure signal analysis unit 750 detects the amplitude and voltage generation timing of the sensor signal of the touch sensor Ts where the touch occurs.

When the sensor signal of the touch receiving electrode Rx is greater than the sensor signal in the untouched state, the pressure signal analysis unit 750 may determine that the input sensor signal is based on the pressure sensor voltage Vf. In addition, the sensor signal of the touch reception electrode Rx is a touch detection signal applied by the touch transmission electrode Tx. The application timing of the touch transfer electrodes Tx may be synchronized with the detection timing of the sensor signal.

The voltage of the sensor signal based on the pressure sensor voltage Vf may not be synchronized with the touch detection signal. The pressure signal analysis unit 750 may analyze the voltage amplitude and voltage generation timing of the sensor signal to determine whether the touch action generates the sensor signal or whether the sensor signal is output by the pressure sensor Ps.

FIG. 11 illustrates the operation of a touch sensor according to an exemplary embodiment. First, the touch sensor controller 700 applies a touch detection signal to the touch sensor (S1001). The touch detection signal may include a plurality of pulse signals, and is transmitted to the touch receiving electrode Rx through a capacitor formed at the touch sensor.

The touch sensor controller 700 first detects a sensor signal applied to the touch receiving electrode Rx (S1002). Among the touch detection signals transmitted from the touch transmission electrodes Tx, the sensor signals are signals transmitted to the touch reception electrodes Rx through the mutual capacitor.

The touch sensor controller 700 compares the voltage of the sensor signal with the touch action reference voltage (S1003). When the sensor signal voltage corresponds to the touch action reference voltage during the touch action, the position of the corresponding touch sensor is detected as the touch position (S1004).

The touch sensor controller 700 redetects the sensor signal of the touch sensor determined to be touched (S1005). The pressure generating action is performed based on the sequence of actions performed by the user after the touch action. The time required for pressure sensing can be substantially reduced or minimized by only redetecting the sensor signal relative to the touch sensor Ts at the location where the touch action occurred.

The touch sensor controller 700 compares the sensor signal voltage with the pressure threshold voltage (S1006). The pressure threshold voltage is greater than the voltage generated during touch sensing. The sensor signal voltage output from the pressure sensor under pressure may be set to be greater than the sensor signal voltage of the touch sensor Ts in the untouched state. Therefore, the pressure threshold voltage may be greater than the sensor signal voltage of the untouched touch sensor Ts. When the sensor signal voltage is greater than the pressure threshold voltage, the touch sensor controller 700 determines that pressure is applied at the touch position (S1007).

FIG. 12A is a cross-sectional view showing another embodiment of a touch sensor pattern of a touch sensing unit, and FIG. 12B shows an example of the operation of the touch sensor unit.

12A , the touch sensing unit includes a substrate 910 , a touch sensor 920 , a first elastic layer 930 , a second elastic layer 940 , a pressure sensor 950 , an insulating layer 960 , a common electrode 970 and a protective layer 980 . The substrate 910 may be, for example, a glass substrate comprising a rigid material that does not bend when pressure is applied, or may be a front substrate of a display device.

The touch sensors 920 extend substantially in the row direction or substantially in the column direction, and are connected to an external touch sensor controller to transmit position detection signals and sensor signals.

The first elastic layer 930 is optically transparent and may have a lower elastic modulus than that of the second elastic layer 940 . The first elastic layer 930 has unevenness at its upper portion to substantially increase or maximize the application of external pressure to the pressure sensor 950 .

The second elastic layer 940 includes a material having a larger elastic modulus than that of the first elastic layer 930 , and is easily deformed by external pressure, so that the pressure is applied to the pressure sensor 950 . The second elastic layer 940 may include, for example, polydimethylsiloxane (PDMS) which is transparent and excellent in elasticity.

The pressure sensor 950 includes a piezoelectric element, and may be formed as a film. The film may include, for example, polyvinylidene fluoride (PVDF) polymer, carbon nanotube (CNT)/PVDF, ZnO nanowires, lead-free Mn-doped (K _0.5 , Na _0.5 )NbO ₃ , laminated in the thickness direction, One or more of PZT, Pb(Zr, Ti)O ₃ or and PbZr _1-x Ti _x O ₃ . The piezoelectric element may have a thickness of, for example, about 80 μm or less, and may have light transmittance. In one embodiment, the piezoelectric element may have a thickness of about 10 μm or less. Since the pressure sensor 950 is located on the display surface of the display device, the pressure sensor 950 may have a light transmittance of about 80% or more.

In one embodiment, the number of the pressure sensors 950 may be less than the number of the touch sensors 920, or the pressure sensors 950 and the touch sensors 920 may be arranged in a one-to-one correspondence.

The insulating layer 960 insulates the pressure sensor 950 from the common electrode 970 .

The common electrode 970 maintains a ground (or reference) voltage or a constant offset voltage and includes a transparent conductive layer. The common electrode 970 may include a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or carbon nanotubes (CNT). The common electrode 970 may have a sheet resistance of, for example, about 10 ⁶ ohms/square or more, so that the signal transmitted to the touch capacitor Ct is not hindered by the common electrode 970 . The common electrode 970 may be formed on the entire surface of the substrate, or may be located only in an area overlapping the pressure sensor 950 .

The protective layer 980 may use a thin film substrate such as a PI film or a glass substrate. When a thin film substrate is used as the protective layer 980 , the touch sensor 920 may be formed on the substrate 910 . The common electrode 970 , the insulating layer 960 and the pressure sensor 950 may be formed on the thin film substrate 980 . The first elastic layer 930 and the second elastic layer 940 may be combined with each other, and thus, a touch sensing unit may be manufactured.

Referring to FIG. 12B , when external pressure is applied to the touch sensing unit, the protective layer 980 is pushed inward, and the pressure sensor 950 under the protective layer 980 is pressed. The pressure sensor 950 may include a piezoelectric element. When pressure is applied, a potential difference is created across the opposite ends of the pressure sensor 950 . The AC component of the voltage generated from the pressure sensor 950 passes through the insulating layer 960 and is transmitted through the touch sensor 920 to the touch sensor controller.

FIG. 13 is a cross-sectional view illustrating another embodiment of a touch sensor pattern of a touch sensor unit. 13 , when the protective layer 980 includes a hard coating layer, the touch sensing unit includes a substrate 910 , a touch sensor 920 , a first elastic layer 930 and a second elastic layer 940 . The pressure sensor 950 , the insulating layer 960 , the common electrode 970 and the protective layer 980 are sequentially stacked in the order listed on the second elastic layer 940 .

FIG. 14 shows another embodiment of a touch sensor pattern of a touch sensor unit. Referring to FIG. 14 , the touch transfer electrodes Tx extend in the column direction of the substrate and have rhombus-shaped grooves. The touch receiving electrodes Rx are spaced apart from the touch transmitting electrodes Tx and are located on the inner side of the grooves. The touch receiving electrodes Rx have substantially the same shape as that of the grooves of the touch transmitting electrodes Tx.

Mutual capacitors are formed along the sides of the rhombus where the touch transmission electrodes Tx and the touch reception electrodes Rx face each other to form one touch sensor Ts. The touch reception electrodes Rx may be individually disposed in a column direction along which the touch transmission electrodes Tx extend. The touch receiving electrode Rx includes three diamond-shaped surfaces connected to each other and to the touch signal controller through sensor lines SL1 to SLp.

The pressure sensor Ps is located at one of the three diamond-shaped surfaces of the touch receiving electrode Rx. The pressure sensor Ps may contact the touch receiving electrode Rx on one side. When one electrode of the pressure sensor Ps contacts the touch receiving electrode Rx, the other electrode thereof is insulated without being connected to another conductor.

In one embodiment, the touch receiving electrodes Rx may have a larger area as the distance from the terminal portions of the sensor lines SL1 to SLp increases in consideration of the insulation resistance of the sensor lines. As the distance from the terminal portions of the sensor lines SL1 to SLp increases, the pressure sensor can have a larger area.

The methods, processes and/or operations described herein may be performed by code or instructions executed by a computer, processor, controller or other signal processing device. The computer, processor, controller or other signal processing device may be one of those described herein or in addition to the elements described herein. Because the algorithms that form the basis of the method (or operation of a computer, processor, controller, or other signal processing device) are described in detail, the code or instructions for implementing the operation of the method embodiments may or other signal processing device into a special purpose processor for performing the methods described herein.

The controllers, units, and other processing features of the embodiments described herein may be implemented in logic, which may include hardware, software, or both, for example. When implemented at least in part in hardware, the controllers, units and other processing features may be, for example, various integrated circuits including, but not limited to, application specific integrated circuits, field programmable gate arrays, combinations of logic gates, systems on a chip, microprocessors and any of other types of processing or control circuits.

When implemented at least in part in software, the controllers, units and other processing features may include, for example, memory for storing code or instructions to be executed, for example, by a computer, processor, microprocessor, controller or other signal processing device or other storage devices. The computer, processor, microprocessor, controller or other signal processing device may be one of those described herein or in addition to the elements described herein. Since the algorithms that form the basis of the method (or operation of a computer, processor, microprocessor, controller or other signal processing device) are described in detail, code or instructions for implementing the operation of an embodiment of the method may enable a computer, processing A controller, controller, or other signal processing device is converted into a special-purpose processor for performing the methods described herein.

According to one or more of the above-described embodiments, the touch sensing unit may detect touch pressure using individual island-shaped piezoelectric elements on electrodes of an electrostatic touch sensor. Since no pressure detection signal wiring is required, the touch sensing unit can be easily manufactured.

Example embodiments have been disclosed herein, and although specific terms are employed, these terms are used and will be interpreted in a generic and descriptive sense only and not for purposes of limitation. In some cases, as would be apparent to one of ordinary skill in the art at the time of filing this application, features, characteristics and/or elements described in connection with a particular embodiment may be used alone, or may be unless otherwise indicated Used in combination with features, characteristics and/or elements described in connection with other embodiments. Accordingly, various changes in form and details may be made therein without departing from the spirit and scope of the embodiments as set forth in the claims.

Claims (20)

1. A touch sensing unit, the touch sensing unit comprising:

a substrate;

a touch sensor on the substrate and arranged in an island shape, the touch sensor providing a first signal indicative of a change in self-capacitance of the touch sensor;

a sensor line connected to the touch sensor;

a pressure sensor comprising a piezoelectric material overlying and electrically connected to the touch sensor and arranged in an island shape, the pressure sensor providing a second signal indicative of a voltage from the piezoelectric material; and

a touch sensor controller receiving the first signal from the touch sensor through the sensor line and receiving the voltage from the piezoelectric material through the touch sensor and the sensor line when the piezoelectric material receives a pressure and determining a magnitude of the pressure based on the voltage.

2. The touch sensing unit of claim 1, wherein the piezoelectric material directly contacts the touch sensor.

3. The touch sensing unit of claim 2, further comprising:

an insulating layer coating the touch sensor and the piezoelectric material.

4. The touch sensing unit of claim 3, further comprising:

a common electrode on the insulating layer,

wherein the common electrode overlaps the piezoelectric material.

5. The touch sensing unit of claim 1, wherein the piezoelectric material comprises polyvinylidene fluoride polymer, carbon nanotube/polyvinylidene fluoride, ZnO nanowire, lead-free Mn doped (K)_0.5，Na_0.5)NbO₃、PZT、Pb(Zr，Ti)O₃And Pb (Zr)_1-xTi_x)O₃At least one of (1).

6. The touch sensing unit of claim 5, wherein the piezoelectric material has an optical transparency of 80% or greater.

7. The touch sensing unit according to claim 1, wherein a size of the pressure sensor including the piezoelectric material increases as a distance from a terminal portion increases.

8. The touch sensing unit of claim 1, further comprising:

an elastic layer between the touch sensor and the piezoelectric material; and

and an insulating layer coating the piezoelectric material.

9. The touch sensing unit of claim 8, further comprising:

a common electrode on the insulating layer,

wherein the common electrode overlaps the piezoelectric material.

10. The touch sensing unit of claim 9, wherein the touch sensor receives an AC component of the voltage generated from the piezoelectric material instead of a DC component.

11. The touch sensing unit of claim 1, wherein the touch sensor and the sensor wire are integrally formed.

12. A touch sensing unit, the touch sensing unit comprising:

a substrate;

a touch sensor on the substrate and including a transmit electrode and a receive electrode, the touch sensor providing a first signal indicative of a change in mutual capacitance between the transmit electrode and the receive electrode;

a sensor wire connected to the receiving electrode;

a pressure sensor comprising a piezoelectric material overlying and electrically connected to the receive electrode and arranged in an island shape, the pressure sensor providing a second signal indicative of a voltage from the piezoelectric material; and

a touch sensor controller receiving the first signal through the receiving electrode and the sensor line, and receiving the voltage generated by the piezoelectric material through the receiving electrode and the sensor line when pressure is applied to the piezoelectric material, and determining a magnitude of the pressure.

13. The touch sensing unit of claim 12, wherein the piezoelectric material directly contacts the receive electrode.

14. The touch sensing unit of claim 13, further comprising:

a common electrode overlapping the piezoelectric material,

wherein the common electrode is insulated from the piezoelectric material.

15. The touch sensing unit of claim 12, wherein the piezoelectric material comprises polyvinylidene fluoride polymer, Carbon Nanotube (CNT)/polyvinylidene fluoride, ZnO nanowires, lead-free Mn doped (K)_0.5，Na_0.5)NbO₃、PZT、Pb(Zr，Ti)O₃And Pb (Zr)_1-xTi_x)O₃At least one of (1).

16. The touch sensing unit according to claim 12, wherein a size of the pressure sensor including the piezoelectric material increases as a distance from a terminal portion increases.

17. The touch sensing unit of claim 12, further comprising:

an elastic layer between the receiving electrode and the piezoelectric material; and

and an insulating layer coating the piezoelectric material.

18. The touch sensing unit of claim 17, wherein:

the elastic layer includes a first elastic layer and a second elastic layer, and

the elastic modulus of the first elastic layer and the elastic modulus of the second elastic layer are different from each other.

19. The touch sensing unit of claim 17, further comprising:

a common electrode on the insulating layer,

wherein the common electrode overlaps the piezoelectric material.

20. The touch sensing unit of claim 17, wherein the receive electrodes receive an AC component, but not a DC component, of the voltage generated by the piezoelectric material.

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